There are a surprising number of different ways to do waistbands. I'll cover two main methods: topstitched folded waistband and waistband with grosgrain facing. I'm was also hoping to try and do a bonus post for making a shaped waistband, but as I'm running short of time (and have yet to figure out how!) that can wait til another time. This, of course, is why we didn't cut the waistband pattern piece at the cutting out stage.
Glossary of Terms
• Facing is fabric which has the 'right' side facing the inside of the garment.
• Interfacing is used for stiffening. It is always enclosed (between the outer fabric and the facing) and is never seen once the garment is completed.
• Iron-on or fusible interfacing has a special heat-activated glue on one side, so when you iron it onto your fabric the two fuse together.
Topstitched folded waistband
This method is suitable for medium weight fabrics - thicker/heavier fabrics might suit the ribbon-faced waistband (below) better. Although modern sewing methods tend to avoid having stitching showing on the outside of the waistband, I quite like the look of the topstitched waistband. It seems it was common in the 50s - I've noticed a lot of my original vintage skirts have topstitched waistbands, and it's also described in many vintage patterns.
To make the waistband pattern piece, mark out a rectangle the length of your actual waist size plus a 1" overlap by twice the desired width of your waistband (e.g. 1").
Add seam allowances all the way around, then cut the waistband from your skirt fabric. Press in half lengthways. If your fabric doesn't hold a crease well, run a line of hand basting along this centre line. Fold in the seam allowance of the long edge on the other side of the waistband and press.
Cut a piece of iron-on interfacing the length and half the width of your pattern piece excluding seam allowance (so, your waist measurement plus 1", by the width of the waistband). Lay this along the crease line on the inside of your waistband piece and iron to fuse it to the fabric.
Pin the interfaced side of the waistband to the top of the skirt, right sides together. Line up the right-hand side with the edge of the zip/seam, while on the left there should be an overlap.
Stitch in place, then press the seam with all the raw edges upwards.
Fold the waistband right sides together (your crease will be 'inside out'), and stitch across both ends (leave an overlap on the left side, while on the right side your stitches should just clear the edge of the zipper tape). Clip the corners and turn right side out.
Sandwich the top of the skirt within the folded waistband, so that the fold on the inside covers the stitching lines. Pin on the outside, making sure to catch the inside waistband. It can help to hand-baste it in place if the fabric is slippery or if the pins distort the waistband (often the case, especially with heavier fabrics).
On the outside, topstitch all the way round the waistband, close to the edge.
This is quite a traditional vintage technique, found in many vintage skirt patterns. It's especially suitable for thicker fabrics, which when folded to make a basic waistband would result in an uneven thickness due to the doubled-up seam allowances at the bottom. I've tried to demonstrate this in the diagram below, which shows a cross-section of folded and ribbon-faced waistbands (lighter weight fabrics won't have this pronounced effect, just heavier fabrics like tweeds and woollens):
I've used the waistband piece from my pattern, which is cut on the fold and includes the overlap (which is trimmed off the right side). To make your own, mark out a rectangle the length of your actual waist size plus a 1" overlap, by the desired width of your waistband (e.g. 1"). Add seam allowances all the way around (you won't want more than 1/2" for a 1" waistband, but if you're making it wider than that you can go with 5/8" if you're more comfortable). Cut the waistband from your skirt fabric.
You'll also need a length of grosgrain ribbon the same width as your waistband, and the same length as your waistband pattern (including seam allowances).
Turn over the seam allowance on one long edge and press.
With right sides together, pin the edge of the waistband to the top of your skirt, stitch in place and press.
Pin your ribbon to the waistband piece, positioning it just a fraction inside the seam allowance. Topstitch in place.
Turn the ribbon to the outside (so that the inside of the waistband is showing) and stitch over the ends - next to the zipper tape on the right side, and 1 1/2" from the lapped fold on the left. Trim the excess close to the stitching.
Turn the ribbon back to the inside, then pin and hand-stitch the ribbon to the seam allowance on the inside. Press.
Note: If you like the look, you can of course topstitch the ribbon-faced style of waistband in the same way: after attaching the waistband to the top of the skirt, stitch the ends of the waistband to the ends of the ribbon. Then, position the ribbon on the inside, pin or hand baste in place, and topstitch on the outside, through all layers (ribbon and folded waistband).
You can either add a skirt hook-and-bar fastening, or make a buttonhole in the overlap tab (if your machine doesn't have a buttonhole function, or if the attachments intimidate you, you can hand-work a buttonhole) and sew a button to the underlap.